Used Tool Preheating Equipment for sale (68,642)

Condition: used, 7 pieces Bending tools for a swivel bending machine Length 3000 mm Laodpfx Aob D Ry Rolbeh

Condition: like new (used), Handling equipment for a finger jointing line. Roller conveyors, wide- and narrow belt conveyors, a trim saw conveyor, trim saws, etc. See pictures. With documentation. Good condition, made by Martek in Finland. Ljdpjd Duz Esfx Alboah

Condition: excellent (used), Year of construction: 1995, Tool grinding machine Michael Deckel S5 in very good condition Technical data: >> year of construction 03/1995 >> grinding wheel diameter max.100mm >> spindle speed 5600 1/min >> power consumption 1,5KW >> weight 450KG Ljdpspr U Etefx Alboah Accessories: >> Swiveling dividing head SK40 >> div. mountings SK40 To the machine : Offered is a tool grinding machine of the brand Michael Deckel S5. The machine is suitable for grinding high precision parts. The Deckel S5 is in a very good condition. Mechanically and electrically tested. Take the opportunity to inspect and try this machine on site under power.

Year of construction: 1976, condition: good (used), Deckel FP1 tool milling machine, 3-axis Heidenhain digital readout, machine was overhauled by FPS years ago. Rigid table, SK 40 spindle holder vertical, SK 40 horizontal, accessories: various collets and milling arbors, counter holder, good working condition, paint is no longer so nice, can be demonstrated under power by arrangement. Lodpfxjrhzcue Albsah

Condition: excellent (used), Year of construction: 1991, Manufacturer: Kalfass Pgsb Aeq Htfnsz Hpn Esr Model Number: Universa8060 Lasdpfx Aeq Htfnjlbsh Rate 40units/min Productdimensions 750x 500 x 140mm Maximum width 800mm Dimensions Welder2200 x 1400 x 1800 mm - Oven 1750 x 1350 x 1300mm -Mat 1700 x 600 x 1100 mm (band width 400mm) Compact L-sealer with shrink oven Created for the demand of industrialapplications The Kallfass 8060/650 compact L-sealers in combination with high-performance shrinktunnels. The qualities of this series of machines becomeevident when Subjected to hard, continuous use.

Condition: new, functionality: fully functional, power: 260 kW (353.50 HP), fuel type: electric, color: dark red, overall weight: 42,000 kg, operation weight: 42,000 kg, chain condition: 100 %, axle configuration: 3 axles, Year of construction: 2026, The construction industry is moving away from the "build-demolish-dump" cycle and toward Urban Mining. At the heart of this shift is the Mobile Stone Crusher, a powerhouse designed to turn piles of jagged concrete and brick into high-quality recycled aggregate right on the job site. --- ## 1. The Engineering Logic: From Waste to Wealth In a traditional setup, demolition waste is hauled to a landfill—a process that is expensive, carbon-heavy, and wasteful. A mobile crusher flips the script. It brings the factory to the waste. By processing materials on-site, contractors save on transport costs and produce "Road Base" or "Sub-base" materials immediately. ### Key Components of a Mobile C&D Plant: * Vibrating Feeder: Uses a "Grizzly" bar system to pre-screen fines (dirt/sand) so the crusher only works on the big stuff. * Crushing Unit: Usually a Jaw Crusher (for primary compression) or an Impact Crusher (for better grain shape and higher reduction ratios). * Magnetic Separator: This is the "secret sauce" for C&D waste. It pulls out rebar and scrap metal that would otherwise contaminate the recycled aggregate. * Discharge Conveyor: Transports the finished product to a stockpile. --- ## 2. Technical Specifications & Performance When evaluating these machines, "Throughput" ($TPH$ or Tons Per Hour) is the metric that matters. For C&D recycling, the machine must handle unpredictable feed sizes and varied material hardness. ### Typical Technical Specifications Table | Feature | Specification Range | Why it matters | | --- | --- | --- | | Throughput | 100 – 500 $t/h$ | Determines project timeline efficiency. | | Max Feed Size | 500mm – 1,100mm | Dictates if you need a hydraulic breaker first. | | Power Source | Diesel-Electric or Hydraulic | Dual power (Electric) is better for urban noise/emissions. | | Crusher Type | Jaw or Impact | Impactors provide a more "cubic" final product. | | Mobility | Crawler Tracks | Essential for moving over uneven rubble piles. | --- ## 3. The "C&D" Specialization Recycling construction waste isn't just about "breaking rocks." It’s about cleaning material. Modern mobile units are equipped with: 1. Over-belt Magnets: Specifically designed to lift heavy steel reinforcement bars (rebar) out of the crushed concrete flow. 2. Dust Suppression: High-pressure misting systems to keep neighbors happy and workers healthy in tight urban environments. 3. Active Pre-screening: Removing sticky soil or asphalt fines before they enter the crushing chamber to prevent "plugging." > The Insight: Using a mobile crusher can reduce project carbon footprints by up to 40% simply by eliminating the "truck-in, truck-out" logistics of aggregate management. --- ## 4. Maintenance and Longevity Because C&D waste is highly abrasive (and often contains "surprises" like wood or plastic), maintenance is non-negotiable. * Jaw Plates: Must be flipped or replaced regularly to maintain the "Closed Side Setting" (CSS), which determines the size of your output. Laedpfx Alsq I Nviebeh * Blow Bars: In impact crushers, these are the high-wear items that take the brunt of the force. --- Would you like me to compare the cost-effectiveness of Jaw vs. Impact crushers for a specific type of demolition project, or perhaps look into the environmental regulations regarding on-site crushing?

Condition: new, functionality: fully functional, Year of construction: 2025, A double teeth roller crusher is a type of roller crusher commonly used in industries that involve the crushing of various materials, such as mining, metallurgy, building materials, and chemical processing. This crusher is characterized by its two pairs of closely spaced, parallel, and oppositely rotating rolls with "teeth" or "knurling" on their surfaces. The teeth are designed to grab and crush the material, providing efficient and uniform size reduction. Ledpfx Aeq Nga Uslbjah Here are key features and aspects of double teeth roller crusher equipment: 1. Double Roller Design: - The crusher features two parallel, counter-rotating rollers, each with a set of teeth or knurling on its surface. The dual roller design facilitates a consistent and efficient crushing process. 2. Teeth Configuration: - The teeth on the rollers are designed to grip and crush the material. The arrangement and shape of the teeth may vary based on the specific application and the characteristics of the material being processed. 3. Adjustable Gap Settings: - The gap between the rollers can usually be adjusted to control the size of the crushed particles. This feature allows for customization of the final product size. 4. Material Feed and Discharge: - Material is typically fed into the top of the crusher and is crushed between the rotating rollers. The crushed material is discharged at the bottom of the machine. 5. High Efficiency: - Double teeth roller crushers are known for their high efficiency in crushing various materials. The dual roller design provides a more consistent and controlled process compared to single roller crushers. 6. Versatility: - These crushers are versatile and can be used for various materials, including coal, limestone, slag, clay, and other similar materials. 7. Application in Mining and Processing: - Double teeth roller crushers are commonly used in the mining industry for the crushing of minerals and ores. They are also utilized in other industries for size reduction and processing of materials. 8. Dust and Noise Control: - Some double teeth roller crushers are equipped with features to control dust emissions and reduce noise during operation, improving the working environment. 9. High Torque and Power: - A powerful motor and a robust drive system are essential components to drive the rotation of the rollers, providing the necessary torque and power for efficient crushing. 10. Maintenance and Safety: - Regular maintenance is essential for optimal performance. Safety features, such as emergency stops and safety guards, are often incorporated to ensure safe operation. 11. Application in Size Reduction: - Double teeth roller crushers are effective in size reduction and are suitable for applications where precise control over the final product size is crucial. It's important to note that the specific design, features, and applications of double teeth roller crushers can vary among different models and manufacturers. When selecting or using this type of equipment, it's advisable to refer to the manufacturer's guidelines and specifications for proper operation and maintenance.

Condition: new, Year of construction: 2025, A sand aggregate production plant is a facility where various types of aggregates (such as sand, gravel, crushed stone, or recycled concrete) are produced for use in construction and other applications. These plants typically include various stages of processing, from raw material extraction to the final product. Here are the key components and processes typically involved in a sand aggregate production plant: 1. Raw Material Extraction: Lsdpfsq Ngb Dsx Albjah - Quarrying or Mining: Aggregates are often extracted from quarries, mines, or riverbeds. Depending on the type of aggregate, the extraction process may involve drilling, blasting, or dredging. 2. Primary Crushing: - Jaw Crusher or Gyratory Crusher: The extracted raw material is usually transported to the plant and fed into a primary crusher, where large rocks are broken down into smaller pieces. 3. Secondary Crushing: - Cone Crusher or Impact Crusher: The crushed material from the primary crusher may undergo further reduction in size through secondary crushing. 4. Screening: - Vibrating Screens: After crushing, the material is often screened to separate different sizes of aggregates. This process ensures that the final product meets the required specifications. 5. Washing: - Sand Washers: In some cases, especially for sand production, washing is done to remove impurities, clay, and fines from the aggregates, ensuring a cleaner and higher-quality product. 6. Grading and Sorting: - Classifiers or Graders: After washing and screening, the aggregates may go through additional processes to separate them based on size or quality. 7. Stockpiling: - Stockpiles: The final aggregates are usually stockpiled for storage before being transported to construction sites or other end-users. 8. Aggregate Storage and Handling: - Storage Bins or Silos: Larger production plants may have storage facilities, such as bins or silos, to store different types and sizes of aggregates before distribution. 9. Quality Control: - Laboratory Testing: Regular quality control testing is performed on aggregates to ensure they meet specifications for strength, size, gradation, and other properties. 10. Environmental Considerations: - Water Management: Some plants incorporate water management systems to recycle and reuse water used in the washing process, minimizing environmental impact. 11. Transportation: - Conveyors or Trucks: Aggregates are typically transported from the production plant to construction sites by conveyors, trucks, or other means.

Condition: new, functionality: fully functional, Year of construction: 2025, For crushing dolomite and phonolite rocks, various types of rock crushing machines can be employed, depending on the characteristics of the rocks and the desired final product specifications. Here are some common types of crushers that may be suitable for processing dolomite and phonolite: 1. Jaw Crusher: - Jaw crushers are commonly used for primary crushing and can handle hard and abrasive materials. They are suitable for both dolomite and phonolite rocks. 2. Impact Crusher: Lajdpfx Ajq Nyuvslbeh - Impact crushers are versatile and suitable for both primary and secondary crushing. They work by impacting the material with hammers or blow bars, producing a high reduction ratio. Impact crushers can be effective for shaping the final product. 3. Cone Crusher: - Cone crushers are often used for secondary or tertiary crushing. They are suitable for processing harder rocks and can produce well-shaped and fine-grained aggregates. 4. Gyratory Crusher: - Gyratory crushers are used for large-scale primary crushing. They have a conical-shaped head and are well-suited for handling abrasive materials. However, they are less commonly used than jaw or cone crushers. 5. Vertical Shaft Impact (VSI) Crusher: - VSI crushers are suitable for shaping and producing artificial sand. They operate by throwing the material against a set of anvils or impellers to break it down into finer particles. 6. Hammer Crusher: - Hammer crushers are used for crushing softer materials and may be suitable for rocks like phonolite. They operate by applying force to the material, causing it to break along natural fault lines. 7. Roll Crusher: - Roll crushers are used for reducing the size of friable materials. They consist of two counter-rotating rolls that compress the material between them. 8. Screening Equipment: - After the initial crushing stage, screening equipment such as vibrating screens may be used to separate different sizes of crushed material. 9. Dust Suppression Systems: - Crushing operations can generate dust, and dust suppression systems are used to minimize environmental and health impacts. 10. Mobile Crushers: - Mobile crushers, including crawler mobile crushers, offer flexibility and mobility, allowing them to be used directly at the quarry or job site. When selecting a crusher for dolomite and phonolite rocks, consider factors such as the hardness of the material, the desired final product specifications, and the production capacity required. Additionally, it's important to integrate the crushing process into an overall plant design that may include screening, conveying, and washing equipment depending on the specific needs of the application.

Condition: new, Year of construction: 2026, HSI Crusher and Impact Crusher: Efficient Solutions for Limestone and Talc Crushing Introduction An HSI crusher (Horizontal Shaft Impact crusher) is a highly efficient crushing machine widely used in mining, quarrying, and aggregate production. As a key component in a limestone crushing plant, it delivers precise shaping and high reduction ratios. Whether used as a limestone crusher or talc crusher, the HSI impact crusher ensures consistent particle size and superior performance across various materials. Features of HSI Impact Crusher High Crushing Efficiency The impact mechanism uses high-speed rotors and blow bars to achieve fine and uniform crushing results. Versatile Applications Suitable for medium-hard to soft materials such as limestone, talc, gypsum, and coal. Adjustable Output Size Hydraulic or mechanical adjustment systems allow easy control of product size. Durable Components Wear-resistant blow bars and liners extend service life and reduce maintenance costs. Easy Maintenance Quick access doors and modular design simplify inspection and part replacement. Energy Efficiency Optimized rotor design and balanced operation minimize energy consumption. Technical Specifications (Typical Range) Model:1214 Max input size： 300 mm, Capacity: 100-140 t/h Model:1315 Max input size: 350mm Capacity: 150-200 t/h Specifications may vary depending on material hardness and feed size. Applications Limestone Crushing Plant: Primary or secondary crushing of limestone for cement, aggregates, and construction materials. Talc Crusher: Fine crushing of soft minerals like talc and gypsum for powder production. Aggregate Production: Produces cubical-shaped aggregates ideal for asphalt and concrete. Recycling: Effective for crushing concrete, asphalt, and demolition waste. Why Choose a Reliable Impact Crusher Manufacturer Selecting a trusted impact crusher manufacturer ensures high-quality materials, advanced design, and reliable after-sales service. A professional supplier provides customized solutions for specific materials, such as limestone crusher or talc crusher, ensuring optimal performance and long-term durability. Impact Crusher for Sale Modern impact crushers for sale feature advanced automation, energy-saving systems, and improved wear resistance. They are ideal for operators seeking high productivity, low operating costs, and consistent output quality in both stationary and mobile crushing setups. Conclusion An HSI impact crusher is a versatile and efficient solution for crushing limestone, talc, and other medium-soft materials. With robust design, adjustable settings, and high throughput, it plays a vital role in any limestone crushing plant or mineral processing line. Choosing the right impact crusher manufacturer ensures reliable performance, reduced downtime, and long-term value. Laedpfx Aljq Ny Saobjh

Condition: new, functionality: fully functional, Year of construction: 2026, A stone crushing plant for sand and aggregate making is a facility where stones and rocks are crushed into smaller pieces or gravel. It typically includes several stages of crushing and screening to produce various sizes and grades of sand and aggregate materials, which are essential in construction, landscaping, and other applications. Here's an introduction to the components and processes involved in a typical stone crushing plant: ### Components of a Stone Crushing Plant 1. Primary Crusher: - Purpose: The primary crusher, often a jaw crusher or gyratory crusher, initially breaks down large rocks into smaller pieces. - Function: It handles raw materials from the quarry or mine and prepares them for further processing. 2. Secondary Crusher: - Purpose: A secondary crusher, such as a cone crusher or impact crusher, further reduces the size of the crushed stones. - Function: It refines the material after primary crushing, producing smaller and more uniform-sized aggregates. 3. Tertiary Crusher (Optional): - Purpose: In some configurations, a tertiary crusher like a vertical shaft impactor (VSI) may be used for shaping and fine crushing. - Function: It produces finely crushed materials for specific applications, such as concrete production or road base. 4. Screening Equipment: - Purpose: Screening equipment like vibrating screens or trommel screens separates the crushed materials into different sizes. - Function: It classifies the aggregates into various grades according to size, ensuring uniformity and meeting specifications. 5. Conveyor Systems: - Purpose: Conveyor belts transport materials between different stages of crushing and screening. - Function: They ensure efficient material handling and continuous operation within the plant. 6. Washing Equipment (Optional): - Purpose: Washing equipment, such as sand washers or scrubbers, may be used to remove impurities from sand and aggregate products. - Function: It improves the quality of the final products by cleaning them and removing fines or contaminants. ### Processes Involved - Primary Crushing: Large rocks are fed into the primary crusher and reduced to a manageable size. - Secondary Crushing: The crushed materials from the primary crusher are further processed by secondary crushers to achieve the desired aggregate sizes. - Screening: The crushed and sized materials are screened to separate them into different sizes and grades. Laedpsq N U Duefx Albeh - Material Handling: Conveyor systems transport materials between different stages of the crushing and screening process. Final Product Handling:Finished products, such as sand and various sizes of aggregates, are stored or loaded for transport to customers or construction sites. Applications - Construction: Used in the production of concrete, asphalt, and road base materials. - Landscaping: Provides decorative and functional aggregates for gardens, pathways, and driveways. infrastructure: Essential for building foundations, drainage systems, and structural fill. As for the capacity we have 30 t/h, 30-50 t/h, 50-100 t/h, 100-150 t/h, 150-200 t/h, 200-300 t/h, 300-500 t/h, and both stationary crushing plant and mobile crushing plant are available for option.

Condition: new, number 37 Positionen 28 mm condition neu weight 29 kg Basic set 1 37 pieces, 28mm system, consisting of: Lodpfx Aegazl Rjlboah Clamps: 4 x 280604 Bolt: 8 x 280511 Stop: 6 x 280420.N Angle: 2 x 280110.G Threaded bolt 8 x 280543 Stop 8 x 160415 Accessory set. 1 x 163999 Price plus packaging and transport.

Condition: new, number 57 Positionen 22 mm condition neu weight 66 kg Lsdsgazmropfx Albsah Set 2 57 pieces, 22mm system, consisting of: Clamps: 6 x 220610.1 Clamps 4 x 220630.1 Prism 4 x 220645.1 Bolt: 18 x 220511 Magnetic bolt 4 x 220740 Stop: 6 x 220410.N Stop: 6 x 220420.N Stop: 2 x 220426.N Angle: 4 x 220110.N Angle: 2 x 220152.N Accessory set. 1 x 223999 Price plus packaging and transport.

Condition: excellent (used), Tool setting device Laodpfxshc I Uvj Albjh (24310) For SK 50

Condition: new, number 27 Positionen weight 52 kg condition neu 28 mm P-Set 1:27 pieces, 28mm system (15mm), consisting of: Clamps: 5 Sk. 100 / 350mm Lsdpegp Dyuefx Albjah Stop: 2 pieces 500mm Stop: 2 pieces 150mm Angle: 2 pieces 175 x 175mm Flat angles: 2 pieces. 350 x 250mm Flat angles: 2 pieces 275 x 150mm Eccentric discs 2 pcs. 100mm Quick release bolts: 10 pcs.

Condition: new, clamping range of chuck 10 - 200 mm height 67,5 mm daylight 65 mm external diameter Futter 200 mm external diameter Spannhebel 360 mm weight 4 kg Characteristics: • Self-centering. • Reversible jaws. • Fixed clamping levers allow fast workpiece changes. • Low weight and flat design minimize the center of gravity. The D-D quick chuck enables a quick product change and is suitable Laedefv Awlepfx Alboh excellent with frequent component changes. You do not need a loose one Quick release wrench, as the levers are integrated into the quick release chuck.

Condition: new, clamping range of chuck 80 - 280 mm height 67,5 mm daylight 100 mm external diameter Futter 300 mm Lajdpfx Aefv Awpjlbsh external diameter Spannhebel 480 mm weight 13 kg Characteristics: • Self-centering. • Reversible jaws. • Fixed clamping levers allow fast workpiece changes. • Low weight and flat design minimize the center of gravity. The D-D quick chuck enables a quick product change and is suitable excellent with frequent component changes. You do not need a loose one Quick release wrench, as the levers are integrated into the quick release chuck.

Condition: new, number 57 Positionen weight 98 kg condition neu 28 mm Set 2: 57 pieces, 28mm system, consisting of: Lsdpfx Asfh Uw Rjlbeah Clamps: 6 x 280610.N Clamps: 4 x 280630.N Prism: 4 x 280648.1.N Bolt: 18 x 160511 Magnetic bolt 4 x 280740 Stop: 6 x 280410.N Stop: 6 x 280420.N Angle: 4 x 160110.N Angle: 2 x 280152.N Angle: 2 x 280162.N Accessory set. 1 x 283999 Price plus packaging and transport.

Condition: excellent (used), grinding wheel (ØxWxd): 125 x 20 x 20 mm Speed: 2800 rpm longitudinal adjustment: 130 mm Ljdpfx Ajfqicxelbeah cross adjustment: 80 mm height adjustment: 65 mm rake angle: +25° to -10 Dimensions WxDxH: approx. 550 450 450 x 650 mm Weight: approx. 70 kg

Condition: new, Special die and stamp ( 28477) Make Bosch Number 2608639902 suitable for GNA 1,3 GNA 1,6 GNA 2,0 unused in original box Lajdjtqlq Dspfx Albsh

Condition: used, Year of construction: 1990, x-travel 600 mm y-travel 400 mm z-travel 420 mm Ledpfotqmm Asx Albsah control TNC 355 Heidenhain Main spindle: turning speed range - main spindle 20 - 4.000 min/-1 power capacity - main spindel 7 kW transmission ratio 3 tool taper SK 40 distance spindle /table 127 - 567 mm spindle diameter in front bearing 55 mm stroke of quill vertical 75 mm tool clamping 10 kN swivellable +/- 90 ° work table: table surface area 900 x 458 mm T-slots 7x 63 x 14H7 feeds: feed range 1 - 5.000 mm/min Feed force 5,4 kN rapid traverse ( X / Y / Z ) 7 / 7 / 6 m/min total power requirement 13 kW weight of the machine ca. 3,0 t dimensions of the machine ca. 4,0 x 4,0 x 2,1 m Tool Room Milling Machine - Universal HERMLE - UWF 900 E - Spindle-Head swivable +/- 90°

Condition: new, number 31 Positionen 22 mm condition neu weight 43 kg Lasdpfeulbb Rjx Albeh Set 1 33-piece, 22mm system, consisting of: Clamps: 4 x 220610.1 Clamps 2 x 220630.1 Bolt: 12 x 220511 Stop: 4 x 220410.N Stop: 4 x 220420.N Angle: 2 x 220110.N Angle: 2 x 220152.N Accessory set. 1 x 223999 Price plus packaging and transport.

Condition: excellent (used), 1 lot SK 45 holders 60 pieces different versions 24 pieces are from Sandwik Coromant 24 various designs: Collet holders Lsdpfjt Uaw Aex Albsah MK 5 holders Cylindrical shank holder Socket holder

Condition: new, range L-W-H 1680 x 470 x 1050 mm weight 137 kg 7 St. Internal dimensions of upper drawer 124.5 x 40 x 9.5 cm (WxDxH) Internal dimensions of medium drawers 78 x 40 x 6.5 cm (WxDxH) Inner dimensions of bottom drawer 78 x 40 x 14 cm (WxDxH) Interior dimensions of cabinet on the left including trash can 25 x 42.5 x 71 cm (WxDxH) Interior dimensions of cabinet on the right including shelf 41 x 42.5 x 54 cm (WxDxH) Maximum loadable weight 500 kg Worktop material wood Material of the drawer handles: aluminum Wheel material PP and PU Housing material metal Packed dimensions 1745 x 520 x 995 mm Packaging weight 136.5 kg Lsdpfx Alsu Imfboboah

Condition: new, range L-W-H 1830x510x1860 mm weight 195 kg 15 St. weight max. in kg 700 kg Professional workbench / tool trolley Dimensions of the right 3 upper drawers 41.5 x 39 x 8 cm. Dimensions of the right 4th drawer 41.5 x 39 x 15 cm. Dimensions of the right 5th drawer 41.5 x 39 x 23 cm. Dimensions of the middle 3 upper drawers 83.5 x 39 x 8 cm. Dimensions of the middle 4th drawer 83.5 x 39 x 15 cm. Dimensions of the middle 5th drawer 83.5 x 39 x 23 cm. Dimensions of the left 3 upper drawers 41.5 x 39 x 8 cm. Dimensions of the left 4th drawer 41.5 x 39 x 15 cm. Dimensions of the left 5th drawer 41.5 x 39 x 23 cm. Dimensions of the back wall 183 x 46 cm. Lsdpfx Aju Imfhjlboah Dimensions of the closets 183 x 30 x 46 cm. Dimensions of the shelf 22.5 x 63 cm. Wheel diameter 150 mm. Maximum capacity of the wheels 175 kg. Per bike. (700 kg total) Maximum capacity per tray 30 kg. Dead weight 195 kg. Overall dimensions 198 x 51 x 186 cm. Packaging dimensions 190 x 60 x 95 cm. Equipped with 4 high-performance steering wheels, 2 of them with brakes. All drawers are equipped with non-slip mats. The open compartment and the drawers can be locked separately. Solid wood worktop 4 cm thick. Solid pullouts with ball bearings (double bearings)